Method of making buckets for turbines.



C. W. DAKE.

METHOD OF MAKING BUGKETS FOR TURBINES.

APPLIUATION FILED D5010, 1913.

1, 12%?49. Patented Feb. 9, 1915.

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UNITED STATES PATENT OFFICE.

CHARLES W. DAKE, OF CHICAGO, ILLINOIS, ASSIGNOR T0 PYLE-NATIONALELECTRIC HEADLIGHT COMPANY, OF CHICAGO, ILLINOIS. A CORPORATION NEWJERSEY.

METHOD OF MAKING BUCKETS FOR TURBINES.

Application filed December 10, 1913.

To all whom it may concern Be it known that I, CHARLES W. DAKE, acitizen of the United States, residing at Chicago, in the county of Cookand State of Illinols, have invented a certain new and usefulImprovement in Methods of Making Buckets for Turbines, of which thefollowing is a specification.

My invention relates to a method or process of maufacturing buckets of apeculiar shape and type for application to the rotor ring or wheel forthe purpose of making the rotor of a turbine.

The description of my invention is aided by the drawings forming part ofthe specification, Wherein- Fi ure 1 is a plan view of a piece of sheetmeta Fig. 2 is a plan view showing the first step in two alternativeforms; Fig. 3 in like manner showing the first two steps; Fig. 4, thefirst three steps; Fig. 5 is a cross section on the line 55 of Fig. A;and Fig. 6 a cross-section on the line 66 of Fig. 4. Fig. 7 is a sideelevation of the bucket comlete. P Like parts are indicated by the sameletters in all the figures.

In describing the method and process I shall refer to these drawings asmeans of explaining the successive steps.

I first take a sheet of metal usually in the form of a long ribbonpreferably wound or rolled. This is straightened out as it is paid oflpreparatory to carrying on the various steps of the process. The firststep of the process consists in stamping out the blank A insubstantially the form indicated in Fig. 2. In my preferred method ofworking my process, I do not cut the blank A from the sheet metal at thedotted line A but this may be done. The blank A has the outlinenecessary to form the bucket and if entirely severed from the sheet ofmetal is then fed in any desired manner forward to the cutting machineor table or operator. The second step consists in forming the blank intothe shape B as shown in Fig. 3 so that it has the inwardly turned bucketsecuring lugs 13, B The third step consists in forming the bucket asindicated at C by holding its two ends toward each other or into avertical position and pressing and stretching the bottom of the bucketinto a curved surface. The result is illustrated in Figs. 6 and 7wherein is shown a bucket C with a curved Specification of LettersPatent.

Patented Feb. 9, 1915.

Serial'No. 805,718.

bottom, lateral projecting securing lugs and side walls.

The particular device the making of which is the object of thisinvention presents a good deal of difficulty and there are, of course, agreat many ways of making it.

The process herein set forth-is the result of long investigation andexperiment with a view to ascertaining the best method. After the blankhas been formed by this first process, that is, when the shape has beensubstantially completed so as to furnish when properly folded andstretched and pressed the necessary material for the bucket, it isdesirable that it still be carried by and therefore be attached to thesheet from which it is formed. The two securing pieces must be bent soas to lie outside of the bucket and the bottom of the bucket must bebent or pressed or stretched into a form to present a face ofsubstantially the same curvature as the curved ends of the sides of thebucket. This involves a stretching process. Since the buckets have to bearranged in a series in close proximity to each other, it is essentialthat these curves be properly formed and related. By the succession ofsteps hereinbefore recited, I find that I am able to give to the bucketa proper and permanent form without displacement or dislocation of anyof its parts, the whole being formed so that the curvatures of bothsides of the bottom of the bucket formed by pressing and stretching andthe curves of the two upper edges of the sides of the bucket formed bycutting are not only in proper relation in the individual bucket but inthe series of assembled buckets, or in proper relation to each other.

I claim:

1. The process of forming from sheet metal a bucket for the rotor of aturbine which consists in stamping out a blank in the form indicated soas to leave the blank attached to the sheet with the metal removed so asto form the outline of the blank, then pressing to one side the securinglugs so that they lie outside of the body of the bucket when the latteriscompleted, then forcing into parallelism the two sides of the bucketand pressing and stretching the bottom thereof so that its two surfaceshave substantially the same curvature as the curved edges of the sidesof the bucket.

' 2. The process of forming from sheet the form. dicated so as to leavemetal a bucket for the rotor of a turbinewhich eonsists in tamp ut b1mkie attached to the sheet, said blank so 'formed havin three zonesof.progressively decreasing width, the widest zone being bounded on the.side, removed from. the other zone by a curved line, bendjngthetwo'sides of'the widest zone up and inwardly so that the re inclined onetoward theotherand g the two'end zones toward, oii'eka'iiot er I intoparallelism substantially at right angles to the central zone and andstretch- 11 1 the centralzone into a euryedshape .to su stantiallyconform on its outsideflith 15 the curved line bounding the widest zone.

' In testimony whereof, I aflix my signature in the presence of twowitnesses this 8th day of December,'1913.. CHARLES W. DAKE.

' Witnesses:

- a PQE Q 1m: tmnran.

